Laropiprant is a drug, which was used in combination with nicotinic acid (also known as niacin) and was known under tradename: tredaptive. Tredaptive was indicated as adjunctive therapy to diet for use in patients with primary hypercholesterolaemia (heterozygous familial and non-familial) or mixed dyslipidaemia. The marketing authorisation for Tredaptive has been withdrawn at the request of the marketing-authorisation holder due to increases in side effects with no cardiovascular benefit. Laropiprant is a selective antagonist of the prostaglandin D(2) (PGD(2)) receptor subtype 1 (DP1). It also has the affinity to interact with thromboxane A2 receptor (TP), although it is approximately 190-fold less potent when compared to DP1. Activation of TP has been shown to induce platelet aggregation in vitro, whereas activation of human platelet DP1 inhibits platelet aggregation. These in vitro data indicate that laropiprant may alter platelet function either by enhancement of platelet reactivity through DP1 antagonism or by inhibition of platelet aggregation through TP antagonism. Also were clinical trials phase II for the laropiprant alone, there were shown, that drug did not demonstrate efficacy in asthmatic patients or patients with allergic rhinitis.